How You Can Eliminate a Food Allergy

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It’s not completely clear how, but scientists think a combination of factors, from genetics to the environment, play a role in children developing allergies to food such as peanuts, milk or shellfish. Many children will outgrow their food allergies. But for those who don’t, physicians have figured out a way to harness the body’s immune response to eliminate allergic reactions to food. Eli Silver, MD, a pediatric allergy and immunology specialist at UH Rainbow Babies & Children’s Hospital, explains.


Transcript

Macie Jepson

So, Pete, when do you remember the first time that you thought, uh oh, one of my kids has allergies?

Pete Kenworthy

Yeah. I wasn't really thinking about it. We kind of knew right away. Right? One of my sons was two years old. We were over at a friend's house, and he ate a sesame covered cashew and shortly thereafter, his lips blew up. He started throwing up. The ambulance came, you know, overnight hives, all the mess that you would associate with what I think would be a, you know, a typical allergic reaction to something. So, we, we knew pretty quickly what had happened.

Macie Jepson

You knew something was bad, for sure. I can't imagine living my entire life as a parent with that fear for my child or much less living with that allergy myself. I mean, that's overwhelming. Hi everybody. I'm Macie Jepson.

Pete Kenworthy

And I'm Pete Kenworthy and this is Healthy@UH. And Macie, certainly any parent with a child with allergies would love to figure out a way to get rid of those allergies. It would make life so much easier.

Macie Jepson

Or just some really specific answers about how to live with them. All right. So, let's get you and the 4% of Americans who have food allergies some answers, Pete. University Hospitals pediatric allergist and immunology specialist. Dr. Eli Silver is our guest today. Thank you for joining us, Doctor. We really appreciate it. It sounds like Pete wants to talk about whether it's possible to make food allergies go away. And we're going to get to that in just a minute, but first, what causes an allergic reaction in the first place?

Dr. Eli Silver

So, we have immune system, and it's supposed to protect us against viruses, bacteria, and other threats. Immune system makes an antibody. It attacks the bacteria and defends us. Sometimes the immune system can make an antibody against the food like peanut, and suddenly when the body is exposed to peanut, the immune system thinks it's under attack and mounts a defense that we call the allergic reaction.

Pete Kenworthy

So, I guess, clear this up for me, right? You're basically, you're saying that the body can misunderstand certain things or what some people, you know, 90 some percent of people can eat peanuts fine and have no reaction. But for some people, the body doesn't agree with that. Is it something you're born with? Is it something that happens after you're born? What makes that happen? Is it just something that happens to some people and doesn't happen to others?

Dr. Eli Silver

It's a combination of genetic risk factors and environmental exposures. We do know that the peanut allergy has almost tripled in the last, the rate of the peanut allergy has tripled in the last 20 years. And it's not just due to a ascertainment where we diagnose it. We are more aware of it. It's just, if you compare test results, you see that more kids these days react to peanut, as opposed to, if you look at the 1960s, 1970s and 1980s. So, there are some environmental factors that are happening, but there is also some genetic factors that are happening. We do know, for example, that parents who come from countries like India or Guatemala from kind of like, you know, outside of the United States, they have very few food allergies and yet their kids will have more food allergy than the baseline sort of kids from, you know, born in the United States. So, there is something that was both the genetics, as well as the exposures that you get.

There are various hypothesis about it, the most common sort of one that has traction is called the hygiene hypothesis, where living in the United States, the immune system does not get…we live in more clean environment and the immune system doesn't get enough traction to learn to fight infections and bacteria so it starts to search out other targets. Some things are just kind of like step back. There are different mechanisms built into the immune system. There are different sort of system and defenses, and pretty much everyone who is born is born in a more allergically inclined immune system. And something happens in the first year of life where the immune system shifts from being more allergically looking and targeting every possible thing that goes inside your body into more tolerant sort of immune system that knows how to differentiate between food that you should eat and viruses that you should fight off. So, for example, there are some studies to show that being born naturally versus C-section has some impact on food allergies. Kids who go through birth canal, they get exposed to kind of like the right bacteria, and they're less likely to develop food allergy versus the ones who are born through C-section. Yet again, you can find plenty of kids born via C-section, who don't have food allergies. So, it's only one of the components, but there has to be some genetics and environmental factors that impact this, what we see here.

Pete Kenworthy

And you talk about that first year, and that's why we're told as parents in that first year of life, don't give your kids things like peanuts, strawberries, things like that, right?

Dr. Eli Silver

That's used to be, but then the whole paradigm shifted 180 degrees. That's what doctors like to do, just, you know, to keep people on their toes. And now it's, the science shows it's the other way around. Introducing foods early on, like, let's say peanut in a safe way so it's not the choking hazard before eight months of age can actually prevent peanut allergy, bringing it into a child into that in the more kind of like state where the immune system is still in flux and trying to figure out it will help it to learn to tolerate the peanut. So, perhaps also one of the factors is delaying the peanut introduction until two years of age may have played the role in potentially increasing their incidents of food allergy.

Macie Jepson

You talked a little bit about genetics already, but I am curious about the environmental factors, because maybe that's something we can change. Can you dig a little bit deeper into what those factors are? And is there something that, because it sounds like Americans are more prone to allergies as well. Is there something that we can do to change that?

Dr. Eli Silver

It will be hard. We, we like our iPhones and we like our sort of clean bed sheets. But yeah, growing up on the farm, taking care of animals, like actually it seems like having a dog in the house being exposed to those things, that's called endotoxin that animals naturally sort of secrete can help to bring the immune system to more tolerant perspective towards the world. Back in olden days, like, you know, 100, 200 years ago, allergies were sign of status. It was sign that you were very refined, and you were so high above the nature, that you became allergic to nature. And that's partly because, you know, allergy was a disease of aristocrats and people who were out in the farms and in the land, they were less sort of, you know, prone to develop allergies in the first place.

Now in, in this, you know, we live in a world where pretty much everyone lives like an aristocrat of 200 years ago. So, I think we're sort of created our own disease. And it would be, I guess, there's things could be done. For example, they found that in Vietnam, kids have very few allergies and, but they, some kids do, but they can actually show the kids who have experienced parasitic infections like parasites, like ascaris, it's like a parasite worm. They actually have fewer allergies. So, there are studies in Europe that tried to see if they can maybe have a controlled exposure of an infant to a parasite. And then of course, treat it with antiparasitic drugs to get rid of the parasite. But during that sort of vulnerable stage to have the immune system exposed to a trigger, to a stimulate that can drive away the allergic inclination.

Pete Kenworthy

So, the environment does play a role here, but I just want to be clear that there are many people who have no chance, right? It's a genetic thing. And they're just predisposed to be allergic to something from the time they're born?

Dr. Eli Silver

Yes. It's just, there are so many factors and the science still tries to understand what they are. There are some evidence that maybe certain bacteria and probiotics can help, and yet we need to know which bacteria it is. It's almost like a piece of puzzle that's three dimensional. It has so many different things to it. And just like when you turn it around, it creates a slightly different picture. I think, practically speaking, we do have some science to recommend introducing certain allergens, like the peanut or the milk or the egg early on, not to delay the introduction later. That seems to reduce the risk of food allergies. Being just out and around the world, let your kids roll in the mud and that can, you know, bring them out. Don't let them sit in front of the TV the whole day. Have them go out hiking and see the, see the nature.

Macie Jepson

Who knew that allergies would be the result of a lifestyle choice that we as Americans have made? So, we talked a lot about what causes this, and it sounds like we’re not going to be able to really control a lot of that. So, let's talk about how we might be able to treat it. And what is that treatment called when you suggest that you might expose a child to something he or she is already allergic to? It sounds kind of scary to me.

Dr. Eli Silver

So, we do have what we call adaptive immune system. And even in its full sort of glory, the immune response can change from year to year. And there is a way to try to redirect the immune response. You can actually increase the immune response by giving vaccines and immunizations, and you can build immune tolerance by giving sort of a chronic re-exposure. Immune system is designed in such a way that it should be able to differentiate world and mud to which you should be able to not react versus an allergen and attacker, well, a pathogen to which is, should be sort of defending yourself. So, an interesting experiment could be done. Let's say if you take a flu shot and you give a person the flu shot day after day after day, instead of developing immunity against the flu, the immune system will think maybe this flu shot is basically part of the nature.

Maybe this is just the dust, and it will actually begin to ignore the influenza, which is not something you want when you're dealing with the flu virus, but it is something you want maybe when you have, when you're dealing with a food allergen.

So, if you can find a way to get the food allergen into a child, don't do adult, and have them exposed to it on a regular basis, the immune system will begin to develop tolerance towards it. And eventually it might even give up on the allergy altogether.

They're almost like two stages that are happening here. First stage is called desensitization where temporarily the immune system decreases the reactivity. And we can discuss in just a moment what that sort of entails, but then hopefully that will progress towards a tolerance, meaning that even if you stop the daily exposure, the allergy does not return or does not come back. So, those are kind of like the two ideas. And the way desensitization works is that we have these immune antibodies, and they are the ones that are necessary to produce an allergic reaction. These antibodies are very good at what they do, but they're not limitless. There is a limited supply. It's almost like an ammunition that you have. And if you can find a way to deplete the ammunition, the body can't react. You just don't have the ammunition to do it. Now, the ammunition is restocked and made every day, but as long as you keep using it up and never let it build up to a high enough amount to cause a reaction, you remain desensitized.

So, practically speaking, how it is done is we would have a person, let's say a child who is allergic to sesame seeds or to cashew, and we give them something on the count of .0150 (one 50 thousandths) of a cashew. That's a such a tiny amount that nobody reacts to that. There's just not enough cashew to cause this systemic reaction, but it is doing something. It's using up a little bit of those antibodies without triggering a reaction. And if you keep doing this dose day after day after day, after about a week or two, there is a little bit decrease, less of that antibody so you can increase the dose slightly higher. And now that dose will use up even more antibiotics at a higher rate. And eventually, usually within about three to four months, the child reaches a point where they can eat a whole cashew and they don't have a reaction just because they don't have enough antibody to have symptoms. If they start doing this, then eventually they'll go back to square one. May take two weeks, may take a month, but they will go back to square one. But as long as they keep on doing it, now they can actually tolerate. And I guess what doesn't kill you makes you stronger in the way. Their immune system will begin to learn that cashew is OK. And the therapy, we still don't have a good way to predict who and how soon we'll reach this point of tolerance. But overall studies show that after about five years, 80% of kids may enter a state of sustained unresponsiveness where if they stop the daily peanut or the daily cashew, the allergy does not return.

Macie Jepson

Just to be clear, Pete needs to do this under medical supervision. Correct?

Dr. Eli Silver

Yes, yes. Do not try it at home.

Macie Jepson

I just wanted to make that point.

Pete Kenworthy

Of course. Yeah. So, let me run through this little list I have in front of me, and it's not long, but the most common allergies, and you can correct me if I'm wrong here, but peanuts, tree nuts, milk, eggs, soy, fish, and shellfish. That's the list that I found. And I guess my question here is twofold. Do these ever go away on their own? Right? Some parents find it at a very early age like we did, and we think, well, maybe it'll go away. And then the second part of that question is if they don't go away on their own, are some of those easier to get rid of than others?

Dr. Eli Silver

There is a new kid on the block. It's the sesame seed allergen, which is becoming up and coming allergen surpassing even some of the ones mentioned in the list, which is a little bit tricky because sesame seed is not declared in the food packaging unlike peanut which says contains peanuts or contains milk. So, that's something to watch for. And with food allergens they're not sort of all doing the same natural history. Some of the food allergens, like the milk and the egg and the wheat, there's a high probability of outgrowing these allergies. By that, I mean about 85% of kids may eventually grow out, and it could happen. Usually happens around five, six years of age, but it can go all the way into the puberty and young adulthood where they can grow out of it. Whereas some kids may retain the food allergy. Peanut allergy resolves naturally in about 22 to 25% of children. And the tree nut allergy may go away in only 5% of kids.

But I think it's important to draw a distinction between being sensitized to something versus being allergic to something. Because that's where it comes about, this question about is the allergy test is actually, is it accurate? Because there are kids who have detectable antibodies against peanut and they can eat it and nothing happens. Such kids would be called sensitized because they do have an antibody; they're just not allergic. So, how accurate are these tests? Well, they're pretty accurate. If the accuracy is defined by finding the antibody, they will find the antibody. If you have it, it will find it. But what the test doesn't account for is there are other mechanisms built in the immune system that deactivate the antibody and prevent it from carrying out its function. So you can actually have a child with a detectable antibody in the reactive skin test, let's say to sesame seed and that they can eat it, and they are fine. And that's where you have to have a finesse of an allergist to help you guide and figure out whether this is something that you should avoid, or you may eat. In the United States about 25% of the population thinks they have something that they are allergic to, but only the food allergy is only about four to 5% of population. So, a lot more people think they are allergic than they truly are.

Macie Jepson

As in gluten?

Dr. Eli Silver

Yeah, the bane of allergy. Yeah.

Pete Kenworthy

But you're telling me that the skin test may falsely reveal allergies. Is that what you're saying?

Dr. Eli Silver

Skin test is a little bit tricky. It's a very sensitive test. It rarely misses an allergy, but it's possible to have skin reactivity and yet on the inside to be able to tolerate the food. It's actually some of these mechanisms to build tolerance can happen on the inside. So, some kids who are truly allergic to let's say egg, they may enter a stage where on the inside, they're not allergic anymore, but the skin test still retains some reactivity. If they eat egg, nothing really happens unless they slobber the egg on their face and they may, they might get a little bit of a superficial reaction. As they keep on eating egg more and more and more even the skin reactivity disappears. So, generally I don't use skin tests to follow allergy over time. I rely more on the blood testing to tell me when it's time to introduce.

And that brings me to a point that the food challenge or actually trying the food under allergist supervision is probably the golden standard of proving if someone is not allergic. We don't do food challenges to prove someone is allergic. That could be gained from getting a history and doing the tests. But over time, as time goes by and we begin to suspect maybe the allergy has resolved, the food challenge would be a way to confirm that impression.

Macie Jepson

So, Doctor, you mentioned skin test, blood test, food challenge. What is the best first step?

Dr. Eli Silver

The first step, it would be getting history, because a lot just asking the patient, interviewing them, hearing their symptoms can help guide us to understand we're dealing with a real allergy, or maybe this is just some sort of a food intolerance like lactose intolerance. But once we are on the pathway on the march suspecting that allergy is involved, the blood test tests the amount of antibody inside the blood. The skin test looks for reactivity when the allergen actually touches your skin. The blood test can only detect antibody after a certain limit. And below that limit it can’t detect it anymore. Even if the antibody is there and can cause harm, the blood has just can't get it all the way. But the skin test doesn't have the limitation of, the detection limit. You've put it on the skin. If you have reaction you, you got it. The antibody is there. It just doesn't tell me the number, how high it is. So, following allergy over time, the skin test may not significantly change. It keeps on reacting, but the antibody, that I could track it over time, and we don't have to wait for the skin test to become negative before we allow the child to have a food challenge. A lot depends on what the antibody level in the blood is. If it's detectable or if it's low, it's undetectable.

Pete Kenworthy

Can we give good news to parents of children with allergies? Like the good news is we can get rid of X number of percent of your child's allergies? Or X number percent of peanut or tree nut or sesame or whatever the case may be.

Dr. Eli Silver

Well, the good news, I think the early introduction of the allergens does reduce the risk of developing allergy in the first place by 80%. So, that's a significant upfront risk reduction. And other good news is that some, you know, the kids who do have food allergy and not growing out of it, they could be desensitized using this oral immunotherapy approach, which seems to be quite successful. We have more than a 94% success rate at desensitizing kids to the point where they can eat the food and not have a reaction. Now, of course, there's some caveats to it. They have to keep on taking this dose and to maintain that state of desensitization. But it does make life a little bit more normal.

Macie Jepson

So, Pete, this whole idea of desensitizing seems pretty promising. I mean, how old is your son now?

Pete Kenworthy

He's 13.

Macie Jepson

What do you think?

Pete Kenworthy

Yeah, no, I mean, I think it'd be awesome. Right? So, I guess that's kind of the final question to you, Doctor, right? If parents of children with allergies looking to get rid of them, right? It would certainly make your life easier. Or even adults with allergies who are looking to do the same and maybe it works better on children or adults and you can let us know, but what's that next step? Do I go talk to my primary care doctor, my pediatrician, or do I come to someone like you? What's the first step for people who are looking to take that next step?

Dr. Eli Silver

So, this oral immunotherapy desensitization is a relatively new approach. The protocols have been around for 12 years, but it's still being a bit of a lag between the science and bringing it into the day to day practice. So, for a longest time, I was the only allergist here in Cleveland who was offering this treatment. And I've heard that some other allergists are now becoming expert in this. And the best way to go would be to perhaps speak with your pediatrician or even go online and to see who has had experience in treating and using this oral immunotherapy protocol and coming in for a consultation to see whether you or your child is a candidate for this.

Pete Kenworthy

It must be exciting for you, like exhilarating to cure someone of an allergy.

Dr. Eli Silver

It’s wonderful. I love it. And, you know, I get to prescribe kids candies, peanut M&Ms on a regular basis.

Macie Jepson

And a life without fear.

Dr. Eli Silver

And a life without fear.

Macie Jepson

Which is amazing. Doctor, thank you.

Dr. Eli Silver

Thanks.

Pete Kenworthy

Yeah, we appreciate you being here and appreciate all your expertise. Thanks so much. Remember you can find and subscribe to this podcast on iTunes, Google Play, Stitcher or wherever you get your podcasts. Search University Hospitals, or Healthy@UH, depending on where you subscribe.

Macie Jepson

As always for more health news, advice from our medical experts and Healthy@UH podcasts, you can go to UHHospitals.org/blog.

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